(SALEM) - An 80-something Salem woman whom a law enforcement officer calls "sharp as a tack" helped solve a mystery; the disappearance of her prescription medication.

The woman lives in an apartment complex which is visited monthly by a New Albany pest control business. According to Washington County Sheriff's Department Captain Roger Newlon, the woman noticed every month, after the technician had been in her apartment, some of her pills were missing.

The woman noticed the pills missing in March. So she counted her pills before he visited in April and after he left some of her pills were missing.

A manager with the company, which Newlon says is a reputable firm, came to the lady's apartment the next month and counted the medication before the employee sprayed. Sure enough, when she counted it again after he left, there were pills missing.

In June, law enforcement installed surveillance equipment and recorded the man going through the woman's nightstand, opening a bottle and getting a handful of pills.

41-year-old Brian Book of New Salisbury was interviewed at the sheriff's department Monday. He confessed to the crime and was arrested on three counts of theft and three counts of possession of a controlled substance, both Class D felonies.

The man told police the woman was his only victim, but Newlon says the pest control company has several apartment complexes in both Salem and Pekin and if anyone suspects their medication was stolen, they should call the Washington County Sheriff's Departments.